Sanitary pump with infinitely variable output



Patented Apr. 28, 1953 SANITARY PUMP WITH INFINITELY VARIABLE OUTPUT Gilbert K. Funk, Waukeslia, Wis., assignor to Waukesha Foundry Company, Waukesha, Wis., a corporation of Wisconsin Application July 25, 1949, Serial No. 106,617

- 4 Claims. (01. 103-42) This invention relates to an improved sanitary pump with infinitely variable output.

- It is a primary object of the invention to provide a pump of the sanitary type, such as is particularly adapted for pumping milk and the like, with a fully controllable and yet easily cleanable by-pass which, although inadequate to handle the pump output, nevertheless gives full control of such output so that the mere adjustment of spring loading on the by-pass check valve provides infinite control of pump output from zero to full capacity. Q

Other objects of the invention will appear fully from the following disclosure thereof with par:- ticular reference to the accompanying drawings, in which:

Fig. l is'a view of my improved pump in side elevation, portions thereof being broken away to expose the interior in axial section.

Fig. 2 is a detail view of the end of the pumpas it appears in axial section in a plane at right angles to that of Fig. 1.

Fig. 3 is a view of the pump casing and rotors in end elevation, the cover being only fragmentarily illustrated.

Fig. 4 is an interior front elevational view of the cover.

The pump is preferably of the general type illustrated in my Patent 2,279,136 of April 7, 1942. It comprises a casing 5 provided with bearings for a pair of inter-geared shafts 6 and I carrying rotors 8 and 9 with inter-geared vanes or pistons.

l and H respectively. The casing provides passages l2 and i3, one of which is an inlet passage, and the other an outlet passage, depending on the direction of shaft rotation. At the outer ends of the passages, the casing has pipe couplings M and I respectively. The inner ends of the passages extend into operative proximity to the point where the respective rotors inter-act to displace the liquid pumped.

Detachably connected with the casing 5 to completely expose the pumping chamber when removed, is an end cover l6 held in place by wing nuts ll. In accordance with the present invention, the outwardly extending portion l8 of the cover is provided with a projecting sleeve at l!) having an interior cavity 26 which constitutes a valve chamber. Ducts 2| and 22 bored obliquely in the cover provide communication between the inlet and outlet passages |2, I3 and the bottom of the valve chamber 2|].

Seated within the valve chamber and conforming to the bottom and portions of the side wall thereof is a cup-shaped valve element 25 which is desirably made of resiliently flexible material such as natural or synthetic rubber. The bottom of the cup-shaped valve element covers the end of passages 2| and 22 and constitutes a diaphragm valve controlling communication therebetween. The margins of the diaphragm valve are compressed against the bottom of the chamber 20 by a pressure transmitting collar 26 which is forced inwardly by a retaining nut 21 screwed externally to the sleeve portion l9 of the pump casing cover I6. Removal of the retaining 'nut' 2? permits the collar 26 and the valve element 25 to be lifted bodily from the valve chamber 20, thus fully exposing the valve chamber and th'e passages 2| and 22 for cleaning. v

In order to control the regulating action of the diaphragm valve, I provide a plunger 28 having its head 29 seated against the diaphragm which constitutes the bottom of the cup-shaped valve element 25. A spring 30 biases the plunger in a direction to seat the diaphragm valve on the end of the valve chamber and about the mouthsbf ducts 2| and 22. The outer end of spring 30 engages an adjusting screw 3| which is threaded into the retaining nut 21 and may be held in any desired position by a lock nut 32. I

The ducts 2| and 22 and the valve chamber 20- together constitute a by-pass between the highpressure and low-pressure sides of the pump chamber. Through this bypass, any desired portion of the-pump output can be circulated from the high-pressure side to the low-pressure side, of the pump, depending on the pressure with which the diaphragm valve is seated in the valve chamber. Such pressure is readily predetermined by adjusting screw 3| tovary the com pression of spring 30.

In actual practice, the capacity of the by-pass system doesnot need to be comparable to the capacity of the pump in order to eiiect full control of the pump to deliver any volume from zero to full capacity.

Whatever the reason, the fact is that flow through the pump can be accurately regulated with infinite variation from zero to full pump capacity by simply rotating the pressure-adjusting screw 3| which controls the spring pressure with which the diaphragm valve is seated to regulate flow through the by-pass.

It will be observed that the cup-shaped valve element 25 comprises not only a diaphragm valve, but also packing, whereby no packing which would restrict the freedom of movement of the plunger 28 is necessary. Moreover, from the standpoint of a sanitary pump in particular, it

is noteworthy that the mounting of the adjust ing screw 3| in the retaining nut 27, and the guidance of the plunger 28 in such screw, result in an advantageous construction whereby all of these parts are in unitary assembly with the retaining nut. Thus, when the retaining nut is unscrewed, the pressure-adjusting screwd 1 comes off with it, and the plunger 28, compression spring 30, pressure transmitting collar 26, and the cup-shaped valve and packing element 25, are all free for removal to expose the chamber and by-pass ducts for cleaning.

I claim:

1. In a sanitary pump of the type having rotors with inter-acting vanes 'in apump-chamber provided with inlet and outlet passages independently communicating directly with said chamber, the improvement which comprises aremovable closure therefor having a by-passin said closure between said passages, said by-pass comprising ducts leading from said passages to a common valve chamber having a common .bypass valve controlling flow vthrough the lay-Pass, said by-pass valve comprising a single diaphragm having one face thereof normally closing both said ducts and :a biasin spring acting on the by-pass valve in a direction for the seating thereof, the said spring being provided with .an exposed pressure-adjusting screw, the adjustment of which regulates flow through the bypass to-control the pump output.

2. Ina pump of the type havinga pump chamber with inlet and outlet passages and rot rs with inter-acting vane pistons operatively mounted in said chambensaid passages being independently directly connected :to said chamber, the improvement which comprises the combination of means providing a by-pass including a valve chamber and .a -pai1- of ducts leading irom the inlet and outlet pump passages to :said valve chambena cup-shaped valve in the valve cham ber having .a single .face covering the ends of both'of said .ducts.and constituting a diaphragm valve and packing, means anchoring the said valve marginally in said chamber, intermediate portions of said valve being free of saidanchoring means for seating and unseating movement respecting said ducts, a plunger having a head portion internally engaged with .said valve ,por-

trons, aspiring acting upon said plunger to bias it against the valve portions .in a valve seating direction, .and an adjustable springseat iorreg ulating the pressure with which the diaphragm seats to control .fiow between said ducts.

,B. Ina pump of the character described, having a pumping chamber and pumping means therein, with high-pressure and low-pressure passages leading from'and to said means, the improvement which comprises the combination with means providing a by-pass including a valve chamber having a seat and ducts leading-from the respective passages to said valve chamber and opening therein through said seat, of a cupshaped valve and packing element in said valve chamber having a bottom wall portion constituting a diaphragmvalve cooperating with .said seat, 'a collar extending into said valve ioriorcing its packing portions against said valve chamber, a retaining nut threaded to said valve chamber and in pressure transmitting engagement with the collar, an adjusting screw mounted in said nut and provided with a bore extending toward said seat, a plunger reciprocable in the bore .andhaving ahead engaged with the diaphragm .portion of the valve and packing element, and a spring confined between the adjusting screw and the plunger and adjustably biased by said screw to urge the diaphragm valve portion of said element tofits seat, whereby to regulate flow through said valve chamber between said ducts, the re- .moval of said retaining nut releasing the plunger,

spring,.co1lar and element for withdrawal from said valve chamber.

4. In a pump of the character described coinprising a casing with a pump chamber and a pair of co-acting pump rotors therein, the said casing ing .a removable cover having an outwardly extending portion, the combination with such a cover having a'va'lv chamber cavity in its said outwardly extending portion and by-pass ducts leading 'tothe bottom of said cavity from the inlet and outlet passages aforesaid, of a retaining nut'threaded to the outwardly extending portion of the cover, a collar extending therefrom into said cavity, a valve and packing element of cup-shaped form having a bottom wall portion constituting a diaphragm valve and a :side wall portion fitting interiorly in the cavity and .into which said collar extends in "pressure engagement subject to the'thrust of said nut, a tubular adjusting screw threaded into said nut and ad justablc therein axially "of the nut, a plunger reciprocably mounted in the screw and provided with a head engaged interio'rly with said valve, and a-spring encircling the plunger andconfined between said head and said screw whereby .adjustably to bias said head and valve to a seat in the bottom of said 'valve, chamber cavity, the

said spring being of such a lengthas to be sub stantially relieved of pressure in one position .of

, the screw to permit substantially free flow through said by-pass ducts and valve chamber from' high-pressure to low-pressure sides-of the pump chamber, the adjustment of the screw providing infinite variation of pump :delivery irom a zero to substantially full :flow according to :the

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1 15 1, 338 "Flanders Aug. 25, 187.4 1,103,053 Kiefer' July 14, .1914 1,470,804. Buckingham Oct. 16, 1923 1,743,585 Wiltse Jan. .14, 1930 1,871 535 Lattner Aug. '16, 1932 2,149,969 Lattner Mar. 7, 19.39 2,380,783 Painter July 31, 1945 2,406,973 Trisler Sept. 3, 1946 

